Television system



Aug. 27, 1940. A. ZILLGER 2,213,061

' TELEVISION SYSTEM Filed July 50, 1932 3 Sheets-Sheet l.

. INVENTOR fiR/vo Z/LLGER BY ATTORNEY 27, 1940. A. ZILLGER TELEVISION SYSTEM Filed July 30, 1932 3 Sheets-Sheet 2 INVENTOR fi/P/vo Z/LZ. 65 ATTORNEY MMM I Aug. 21; 1 0 A. ZMGER 2,213,061

TELEVIS ION SYSTEM Filed July 30, 1932 3 Sheets-Sheet 3 INVENTOR fl/r/vo Z/LLG5R BY ATTORNEY Patented Aug. 27, 1940 UNITED STATES PATENT OFFICE.

TELEVISION SYSTEM Ware Application July 30, 1932, Serial No. 626,579

Claims. (01. 178-73) This invention relates to television apparatus and particularly to an apparatus for receiving television impulses sent either over the wire or by radio and translating them into an image thrown '5 upon a screen.

One of the objects of the invention is toprovide a television receiving apparatus in which the modulated light scanning the image is as intense at the beginning of the picture as it is at the end thereof.

Another object of the invention is to provide a television receiving system in which the light spot which scans the screen to produce an image is square or rectangular in shape thus filling up the spaces between adjacent spots.

Another object of the invention is to provide a lighting arrangement for a television apparatus in which there is no necessity for an optical system between the modulated light and the scanning means.

Other objects of the invention and objects relating particularly to the construction and assembly of the various parts will be apparent as the description proceeds.

Several embodiments of the invention have been illustrated in the accompanying drawings in which: 7

Fig. l is a schematic representation of a television receiving system embodying the invention;

Fig. 2 is a plan view of one of the reflecting elements used on the drum of Fig. 1;

Fig. 3 is a perspective View, partly in section, of the lamp used in the apparatus of Fig. 1;

Fig. 4 is a sectional plan View taken on the line 44 of Fig. 3 showing the elements of the lamp;

Fig. 5 is a schematic representation of another television system which incorporates the invention;

Fig. 6 is a front elevational viewof the shutter disc of the apparatus of Fig. 5;.' and,

Fig. '7 is a front elevational view of the lens disc of the construction of Fig. 5.

Broadly the invention comprises a television receiving apparatus in which a modulated light is used which produces a line of light having a thickness substantially equaltothe width of an individual spot of light used for building up the image and having a length corresponding to one dimension of the projected picture. This lamp is preferably arranged in a vertical position and means is provided for one section at a time of this vertical line of light to sweep across the screen, so that tiny squares of light follow each other across the screen in swift succession until 55 the complete picture has been scanned. Thus the light is as strong for the top of the picture as it is for the bottom inasmuch as the intensity of the line of light is uniform throughout'its length.

Referring now more specifically to the draw- "It: ings a lamp i5 is shown in Fig. I connected by means of the wires l l to an amplifier I 2 the input of which may be connected to a radio receiving setfor' directly by means of the input wires li to a television transmission apparatus. The 10- lamp produces a line i3 of light and wil=lbe more fully described hereinafter;

A drum l l 'mounted on a shaft I5 is caused to rotate by a synchronous motor It at a speed corresponding to the speed of Y the transmission 1 apparatus. Where the transmission and receiving apparatus are run on an alternating current circuit which is connected to the same power supply-system the receiving motor will run in synchrony with the transmitting motor and no 9. additional synchronizing apparatus is necessary. Such a motor is indicated in Fig. 1, but it is to be understood that additional synchronizing devices may be applied to the motor if it is adapted to run on a circuit which is normally out of synchrony 35 with the power supply of the transmission set.

The drum I4 is made up of a series of plates H each comprising aflat disc with a hole I 8 in the center and one side cut away to form a straight flat reflecting surface 1 9 which is preferably high- 35 ly polished to make it as good a reflector as persible. The disc may be made oi -any desired metal although I-prefer to use one which will take a high polish such as stainless steel, stellite, nick el, or the like-although softer metals such as Monel metal may also be used. It is desirable, however, to use a metal which will hold the polish without danger 'oftarnishing or the reflecting surface otherwise disintegrating or becoming clouded. Each of the discs I! is provided with 4G a key-way 20 in the side of the .hole 18' and these key-ways in the plurality of discs making up the drum are arranged at slightly different angles successively, so that when the discs are put upon the shaft l5, which is also provided with a keyway, and the key-ways in the discs are lined up, the discs will lie so that each disc isv at an angle to the disc-immediately in contact with it. In this television system which I have selected for purposes of illustrating. my invention, it is desired to receive sixty lines per picturegand hence I- usesixty discs to make up the drum, each disc being at an angle of six degrees with the disc immediately below it or above it so that the" refiectingwsurface; laion each disc is six degrees re moved from the reflecting surfaces of the two discs above and below it. When the drum I4 is rotated at the speed determined by the rotating speeds. of the television transmitter and an observer takes up his position adjacent the lamp I0 he will see in the drum M a portion of the light reflected from the line of light |3 in first one mirror surface and then another until the drum has made one revolution when the complete picture consisting of sixty horizontal lines will appear on the surface of the drum. The drum is preferably rotated at about twenty revolutions per second which conforms to the speed at which television pictures are transmitted at the present time and hence the observer sees twenty complete pictures per second, and as his eye retains the image for a twentieth of a second very readily he will see a continuous natural moving picture. A

mirror 2| may be positioned in the path of the rays at about 45 to the line of light from the lamp to the drum and the image will then appear in the mirror if the observer stands in front of the drawing, or if a screen 22 is placed between the observer and the mirror such as a sheet of ground glass or other translucent material the image will appear on the screen. If desired a suitable optical system 23 may be used to project the image of the drum upon the screen 22.

The lamp I0 is illustrated more in detail in Figs. 3 and 4 and comprises an envelope 24 having the usual inturned press 25 for supporting the elements of the lamp. A flat cathode plate 26 may be supported inside of the lamp upon two support rods 21 sealed in the press 25 and may be made rectangular with a rib 28 attached to the back thereof and extending from end to end. The rib 28 is preferably formed integral with the plate 26 and a wide slot or opening 29 is provided in th plate 26 out deepinto the rib 28, as indicated in Fig. 4, to form a trough in which the discharge occurs. An anode plate 30 is mounted in close proximity to the cathode plate 26 and parallel to it upon support rods 3| which are sealed in the press 25. The plate 30 is provided with a narrow slot 32 which extends parallel to the groove or slot 29 in the cathode plate 26 and is somewhat shorter than this slot but is in alignment therewith. Lead-in wires 33 and 34 are connected to one of the rods 21 and one of the rods 3| for making the electrical connections to the lamp.

The cathode and anode plates 26 and 30 may be made of any suitable metal which can be readily degasified such as iron, nickel, molybdenum, tungsten, or any other of the refractory metals, or softer metals, such as copper or Monel metal may also be used with good results.

With the parts mounted as indicated in Fig. 3 the envelope 24 may be attached to a vacuum pump and the air pumped out of it; At the same time an oven is placed over the lamp to raisethe temperature of the envelope and associated parts to drive out any occluded gases which may be present. When all of the gases are withdrawn, as may be evidenced by the lack of fluorescence when high tension current is directed against the walls of the bulb, I admit an ionizable gas, such as neon, or helium, or the like, or mixtures of such gases at a pressure not greater than 15 mm. of mercury, depending on the kind of gas used, and the lamp may then be sealed off and is ready for use. When such a lamp is connected in the output circuit of a suitable amplifier a discharge is produced inside of the groove 29 in the cathode which may be viewed through the slot in the anode. The discharge is concentrated in the slot and appears as a substantially white light of uniform intensity throughout its length. It thus appears from in front of the anode as a line of light whose width is determined by the width of the slot 32 in the anode. This line of light may be modulated in accordance with the incoming signal as the discharge starts and stop as the signal rises and falls.

It may be desired to insulate the support rods and the back of the cathode from the gas within the tube and this may be done by applying a coating of insulating material 3|a to these parts. This material may be any kind of plastic insulation which will adhere to the parts and can be freed of gases.

While the lamp just described may be preferred I do not wish to limit myself to any particular type of lamp for producing this line of light as many other types may be used, my invention being intended to cover a combination of a line of light with a television apparatus. Other means for producing a line of modulated light are described and claimed in the application of Chester H. Braselton entitled, Discharge lamp for producing modulated light, Patent No. 2,063,580, issued Dec. 8, 1936.

Figs. 5, 6, and 7 illustrate another type of television apparatus which may be used with the invention. Here a scanning disc 35 is provided with sixty spaced-apart openings 36, the center, of the openings being spaced from the center or the disc on a spiral line extending around the edge of the disc with the end of the line nearer the center than the beginning. The radial distance between the beginning and end of the line of centers is equal to the height of the image received while the space between centers of adjacent openings represents the width of the image. Each opening 36 is provided with a lens 3'! which is set into the disc and is used for projecting the image of the light source on a screen 38. The disc 35 with a portion of the lenses 31 mounted in place is shown in Fig. 7. The disc is mounted on a shaft 39 which is driven by a synchronous motor 40 so that it will run at the same speed as the scanning device at the transmitting end of the system.

A second disc 4| is also mounted on the same shaft spaced a short distance from the disc 35. The disc 4| is preferably made of a transparent material such as glass and is provided at its periphery with a blackened portion 42 which extends from the edge of the disc to a point nearer the center than the innermost hole on the scanning disc 35. A series of arcuate lines 43 are provided on the blackened portion of the disc by removing the blackened surface so that the lines become transparent. The transparent lines 43 are so arranged that one line passes through a point opposite the center of each of the holes 36 in the disc 35 and the lines are just long enough to extend from a point half way between two of the holes to a point half way between the next two, as clearly indicated in Fig. 6, the holes 36 being shown in dotted lines. The width of the lines are preferably the same as the width of the line of light produced by the lamp H] and correspond to the width of the horizontal scanning lines.

When the lamp I0, similar to that shown in Fig. 1, is positioned in back of the disc 4| light from the line of light |3 can pass through the disc 4| only where one of the lines 43 is positioned in front of it, the black portion of the disc 4| serving to shut out the rest of the light. When the shaft and disc are rotated, therefore, starting with the position shown in Fig. 5, the line of light is cut first by the outermost transparent line 43 and a small square of light is projected by means of the corresponding lens 3'! onto the screen 38. As the disc moves the square of light thus projected on the screen 38 moves across the screen until a point is reached where the second lens is ready to pick up the image. At this time the second transparent line 43 has reached the light source and the effect is to show a square of light slightly lower and in line with the second lens 31 which therefore projects the second square of light slightly lower upon the screen 38. This process is repeated, the effect being to completely scan the screen 38 with a small square of light.

This represents a great improvement over certain types of television apparatus now on the market which make use of a disc set with lenses similarly to the disc 35 but which use, instead of the light source Ill and. the disc M, a single point light source. The result of this is that the point light source is set half-way between the first and the last holes in the disc, so that the only hole which is actually correctly positioned so as to project the point of light on the screen 38 is hole number 30 which is half-way between the first and the last. The other holes are all slightly either below or slightly above the light source and tend not only to distort the shape of the light source but to dim the light at the upper and lower portions of the picture. In my invention the effect of the line of light and the disc with the transparent arcs thereon is to cause a small source of light to move up and down always in alignment with the holes in the scanning disc. Another advantage arises through the fact that the light source is square and, therefore, all of the space between scanning points on the screen are filled with light whereas where a round light is used unless the light overlaps to a large extent there are dark spots between adjacent points which give rise to lines on the projected picture. My invention tends to eliminate this effect of lines and gives a uniform picture without distortion.

Many modifications may be made without departing from the spirit of the invention and I do not, therefore, desire to limit myself to what has been shown and described except as such limitations occur in the appended claims.

What I desire to claim and secure by Letters Patent is:

1. In an apparatus of the class described a rotatable drum, a plurality of reflecting surfaces arranged on said drum, said surfaces lying in planes substantially parallel to the axis of said drum and said surfaces being relatively long narrow rectangles, the angular relation between them being such that each surface scans one line of the picture and the picture is completely scanned at one revolution of the drum, and a modulated light source comprising a thin line of light positioned adjacent said drum and parallel with the axis thereof.

2. In a device of the class described, a rotatable drum, a plurality of reflecting surfaces on said drum, said surfaces lying in planes parallel to the axis of said drum but each surface having a .width. corresponding to a very small portion of the length of said drum and a length almost equal to the diameter thereof, and a modulated light source comprising a line of light positioned adjacent said drum.

3. In a device of the class described a plurality of plates each having a flat relatively long refleeting edge, means to secure said plates in a stack with the reflecting edges all lying tangent to a cylinder whose axis is the axis of the stack each of said surfaces bearing the same angle to the surface on one side of it as it does to the surface on the other side, means to rotate said stack of plates at a predetermined speed, and means to create a line of modulated light substantially parallel to the axis of said stack of plates and facing it.

i. In a device of the class described an envelope, an ionizable gas within said envelope, means to ionize said gas in accordance with a modulated incoming television signal along a thin line, a drum rotatably mounted on an axis substantially parallel to said line of light, a plurality of relatively long thin reflecting surfaces on said drum arranged transversely thereof in planes parallel to the axis thereof, said surfaces being equally spaced at equal angles to ach other around the circumference of said drum and being arranged in series with the first one at one end of said drum and the last one at the opposite end of said drum, and means to rotate said drum at a predetermined speed so as to scan said line of light.

5. An apparatus for television reception and the reception of electrically transmitted pictures comprising in combination a linear source of light intended to be controlled by the received currents and a rotary system of mirrors, the number of which corresponds to the number of the picture lines, the said mirrors being arranged next to one another along an axis of rotation and distributed at equal angular distances from one .another over the range of rotation, the linear source of light being arranged to lie parallel to the said axis of rotation and to produce its image in the system of mirrors direct without the interposition of any optical system, and the minimum length of the individual mirrors being equal to the length of the picture lines.

ARNO ZIILGER. 

